This paper introduces the application of a calling and queuing system for blood sample collection in a large hospital in China. Besides the basic function, it has following functions. (a) A real name system: get the number according to the laboratory application form to prevent the phenomena of buying a number and an empty number. (b) Two times waiting: the patient should wait at the main hall, then at the blood sampling window so as to improve the work efficiency. (c) The flowchart for an outpatient blood testing is as following: getting the number --> waiting --> blood sampling --> getting the test information report. This system is capable of not only optimizing the work flow, but also improving the clinical environment. It shortens the patient's waiting time and raises the laboratory quality as well.